As is known an eyeglass frame front generally comprises two rims each adapted to receive an ophthalmic lens or more generally an eyeglass lens and joined to the other at the inner (nose) sides by a nose bridge, at each outer (temple) side the rims are provided with pivot yokes for pivotally mounting sidepieces known as temples.
In the case of metal eyeglass frames it is practically compulsory that each of the rims have a slot to permit the mounting of the lens therein. Most often the slots are disposed at the outer (temple) sides of the rims.
It has, however, been proposed, in French Pat. publication No. 2,044,209 to provide the slot at the inner sides of the rims, the nose bridge joining the rims being virtually divided into two substantially parallel pins which extend to either side of the slots of the rims, closure means being associated with the slots for closing the rims around the eyeglass lenses once in position.
This arrangement has the advantage of simplified positioning of the eyeglass lenses, a single operation being sufficient to close both rims enclosing the lenses, and therefore facilitating, if desired, changing of lenses, for example, depending on lighting conditions. It has another advantage of facilitating the adoption of a yoke of any desired configuration on which the temple is pivoted, such a yoke being free of constraints due to its bordering on the slot and the corresponding closure means therefor, or having to be combined with the slot of the closure means.
Yet, in practice, in the embodiment disclosed in the French patent publication No. 2,044,209 mentioned above, in which the eyeglass frame front is made of synthetic material with a central nose bridge split into two pins adapted to be in contact with each other for closing the corresponding rims, the latching means provided for transversely securing the two pins to each other being formed by a separate part, e.g., a screw or clip, to be mounted on the eyeglass front.
The handling of such a separate part, by its very nature, makes the closing of the rims awkward to the detriment of the sought-after simplicity, notably when the rims are closed at the place where they are being worn.
Further, the inadvertent dropping of the part in question in the course of the closing operation, which is always possible, may cause the previously positioned lenses themselves to fall out, which is likely to damage the lenses.